This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This is a proposal to use high end computing to describe flow and mass transport through porous scaffolds in the microscopic level. The objective is to employ images of actual scaffolds used in perfusion bioreactors for bone tissue growth in order to calculate flow and material properties, and in order to develop models that can describe the transfer of nutrients to the bone cells in perfusion bioreactors. The computational approach is to use a flow simulation in conjunction with a Lagrangian method. The lattice Boltzmann method (LBM) is the method of choice for simulating small scale flows in complicated geometries (like porous scaffolds), and it will be combined with the Lagrangian scalar tracking (LST) methodology developed in our laboratory for simulating mass transfer. Modern visualization techniques, like micro-Computing Tomography scans, will provide a detailed, digital view of the 3D pore space in a microscopic scale (10 microns resolution), which will serve as the computational domain for the application of the LBM/LST methodology. Bone tissue development with time will be correlated to the scaffold configuration, in order to propose optimal scaffolds for bone tissue growth. Modeling results will be validated with experiments.